Control system



Se t. 15, 1936. H. s. CGDEN CONTROL SYSTEM Filed Feb. 18, 1936 2 Sheets-Sheet l Inventor: Harold 5.0 den,

19m s Attorney.

Sept. 15, 1936. OGDEN 2,054,683

CONTROL SYSTEM Filed Feb. 18, 1936 2 Sheets-Sheet 2 Patented Sept. 15, 1936 UNITED STATES PATENT OFFICE CONTROL SYSTEM Application February 18, 1936, Serial No. 64,476

10 Claims.

My invention relates to control systems for multiple unit vehicles, more particularly to control systems having metering means for indicating at a plurality of points on the vehicle, the our- 5 rent flowing in the various motor circuits and has a for an object the provision of an improved metering system of this character.

Multiple unit vehicles having a plurality of separate motor circuits associated with various units of the vehicle and a plurality of master control stations, each of which is arranged to control all of the motor circuits have heretofore been provided with control systems including metering means for indicating at each master control station the current flowing in the various mo-' tor circuits. In such previous system, however,

each control station is provided with a group of meters, one meter in each group being connected to each of the motor circuits so that the number of meters in each group is equal to the number of motor circuits. Obviously, the number of meters required in such a system becomes excessive as the number of motor circuits increases and as the number of master control stations increases.

Much is yet to be desired in the simplification of metering systems, of this type and accordingly it is a further object of my invention to provide a control system for a multiple unit vehicle in which each control station is provided with a meter arranged selectively to be connected to any one of the motor circuits of the vehicle.

In carrying out my invention in one form, I

provide in connection with a multiple unit vehicle having a plurality of motor circuits and a plurality of master controllers, a metering system including metering means associated with each of the master controllers, and means associated with each controller for selectively connecting the associated metering means to any one of the motor circuits. More specifically, I provide a meter adjacent each controller and current deriving means, such, for example, as a current transformer, associated with each motor circuit. A plurality of transfer switches are also provided for normally connecting the respective meters to certain of the current transformers and train wires extending between the vehicle units are arranged selectively to be connected by the transfer switches to a selected one of the meters and to certain ones of the current transformers so that an indication of the current flowing in any one of the motor circuits may be selectively obtained on the selected meter.

For a more complete understanding of my invention, reference may now be had to the drawings, in which Fig. 1 is a diagrammatic representation of a control system embodying my invention, and Fig. 2 is a similar representation of a modified form of control system embodying my invention.

Referring now to Fig. 1 of the drawings, I have shown my invention in one form as applied to a multiple unit vehicle comprising a pair of vehicle units A and B, respectively, which are identical in construction and arrangement. It is believed that a comprehensive understanding of my invention may best be had from a description of the operation of the vehicle and accordingly, certain parts only of the unit A will first be described in detail and in the subsequent description of the operation, similar reference numerals followed by the letter 12 will be used to refer to similar parts of the unit B.

- As shown, the vehicle unit A is provided with a pantograph, or current collector, ID for supplying energy from a suitable trolley or conductor (not shown) to a traction motor comprising an armature l I and a field winding i2 through a control box [3 and a reversing switch It, the other side of the motor circuit being provided with a suitable ground connection l5. As shown, the vehicle unit A is a double ended unit arranged for operation in either direction and is provided at its opposite ends with master control stations l6 and H, repectively. The master control station it includes an acceleration controller l8 and a reversing drum l9, while the master control station ll includes a similar acceleration controller 20 and a reversing drum 2 I. Although the acceleration controllers and the reversing drums are shown as separate units more clearly to illustrate the circuit connections through the reversing drums, it will, of course, be understood that these controllers are preferably constructed as one unit, the reversing drums being provided with separate reversing handles in a manner well understood by those skilled in the art,

It will be understood, of course, that the control box l3 may contain any suitable type of acceleration controlling means and, as shown, the acceleration controllers l8 and 20 are connected to the control box l3 in multiple circuit relation by suitable control cables 22 so that either the acceleration controller ill or the acceleration controller 20 is efiective to control the mechanism contained in the control box i3. The reversing switch It, which is indicated somewhat diagrammatically, may be of any suitable type well known in the art and is shown as including a pair of operating windings 23 and 24 connected through suitable 2 2,os4,ess

train wires 25 and 28 to the reversing drums l3 and 2|, the reversing drums being connected in parallel circuit relation, so that either of the reversing drums is effective to control the energize,- tion of the windings 23 and 24.

Associated with the motor circuit of the vehicle unit A is a current transformer 21 and a plurality of meters 23 and 23 are provided, the meter 28 being positioned adjacent the master control station l3 and the meter 23 being positioned adjacent the master control station ll. Arranged selectively to control the circuit connections of the current transformer 21 to the meters 23 and 29, I provide a transfer switch which is shown somewhat diagrammatically as a drum-type, three-position switch which is normally biased to the No. 2, or middle position, and which is provided with a pair of operating windings 3| and 32 which are selectively energizable to operate the transfer switch from the No. 2 position to its No. 1 position, or its No. 3 position, respectively. It will be understood, of course, that any suitable type of three-position switch may be employed, examples of which are well known in the art.

As shown, the transfer switch 33 is provided with a plurality of contact fingers 33 to 40, inclusive, the fingers 33, 34, and 36 being connected to a pair of train wires 4i and 42, the contact fingers 36 and 43 being connected through suitable conductors to the meters 28 and 29 and the contact fingers 3'8, 38, and 33 being connected through suitable conductors to the current transformer 2'5. In order selectively to control the energization of the operating winding 32, I provide a control 5 switch 43 associated with the master control station it and a similar control switch 44 associated with the master control station ll.

As heretofore stated, the vehicle unit B is identical in construction with the vehicle unit A and in order to provide for multiple unit operation of the two vehicles, suitable jumpers 45 are provided for connecting the control cable 22 to the control cable 22b. Similarly. I provide suitable jumpers 43 to 49, inclusive, for connecting the train wires 25, 23, 4i, and 42 to the train wires 25b, 23b, Mb, and 421), respectively,

In describing the operation of the multiple unit vehicle, it will be assumed that the vehicle unit A is the leading unit and that it is desired to operate the vehicle in a left-hand direction, as viewed in the drawings. The control apparatus for the two vehicles is shown in the position assumed as soon as the reversing handle of the reversing drum it has been operated to the forward position. Upon operation of the reversing drum I3 to this position, it will be seen thatan energizing circuit is established for the reversing switch l 4 which may be traced from the positive source of control potential through the contact fingers 5i and 52 on the reversing drum IS, the conductor 53, the train wire 25, and by way of the conductor 54, and the operating winding 23 of the reversing switch M to the ground connection IS, the reversing switch it thereupon being operated to the position shown. Likewise, an energizing circuit is completed for the reversing switch l4b, which circuit extends through the train wire 25, the jumper 46, the train wire 25b, and by way of the conductor 54b and the operating winding 23b, to the ground connection ISb. Thus, it will be seen that the field and armature circuits on the two units are connected through the reversing switches for operation in a forward direction.

Simultaneously, with the establishment of the above described circuits, an energizing circuit is 25, the jumper 43, the train wire 25b, the conductor 64b, the conductor 55!), the auxiliary contacts 58b and 51b on the reversing switch No, the conductor 54?), the auxiliary contacts 59b and-60b on the reversing drum 2th, the conductor 6), the auxiliary contacts 62b and 63b on thereversing drum I9b, and by way of the conductor 64b and the energizing winding 3") to the ground connection lib. It will be apparent that since the auxiliary contacts on the various reversing drums are bridged only when the reversing drums are in the off position, a similar energizing circuit for the operating winding 3| of the transfer switch 33 is interrupted at the contacts 32 and 63 of the reversing drum l3.

The vehicle is now in condition for operation in a forward direction in accordance with the operation of the acceleration controller l8 on the vehicle unit A and it will be apparent that the meter 28 associated with the master control station It is connected through the transfer switch 33 to the current transformer 21 so as to give an indication at the master control station l5 of the current flowing through the motor circuit on the vehicle unit A. This meter circuit may be traced from one side of the current transformer 21 through the conductors 65 and 66, the contact fingers 33 and 31 bridged by the conducting segment 61, the conductor 68,

the meters 28 and 29, the conductor 68, the contact fingers 40 and 39 bridged by the conducting segment 10 and by way of the conductor H to the other side of the current transformer 21. Similarly, it will be seen that the current transformer 21b is connected by the transfer switch 33b to the train wires 4") and 42b which are in turnconnected to the train wires 4! and 42 through the jumpers 48 and 43, respectively, the train wires 4! and 42 being short-circuited through the contacts 33, 34, and 35 of the transfer switch 30. This circuit for the current transformer 21b may be traced from one terminal of the current transformer through the conductors 35b and 66b, the contact fingers 37b, the segment 6'"), the conductor 13b. the conducting segment 14b, the contact finger 35b, the conductor b, the train wire MD, the jumper 48, the train wire' 4!, the conductor 15, the contact fingers 35, 34, and 33, bridged by the conducting segment 18, the conductors l1 and 78 in parallel, the conductor 19, the train wire 42, the jumper 49, the train wire 42b, the conductors 19b and 18b, the contact finger 33b, the conducting segment 80b, the conductor 3|b, the conducting segment 10b, the contact finger 39b, and by way of the conductor lib to the other side of the current transformer.

With the apparatus in this condition, it will be apparent that the operator at the master control station It may obtain an indication of the current flowing in the motor circuit on the vehicle A simply by glancing at the-meter 28. In case the operator desires to obtain an indication of the current flowing in the motor circuit in the vehicle unit B, it is only necessary forhim to depress the control switch 43 located at the master control station It. 1

Subsequent to the closure of the control switch 43, an energizing circuit is established for the operating winding 32 of the transfer switch so,

which circuit may be traced from the positive source of control potential 82 through the control switch 43, the conductor 88 and by way of the energizing winding 92 to the ground connection I5. Thereupon, the transfer switch 89 will be operated to its No. 3 position to disconnect the meters 28 and 29 from the current transformer 21 and to connect the meters 28 and 29 to the current transformer 21b through the train wires. This is accomplished simply by removing the short-circuit across the contact fingers 84 and 95 and by connecting the meters 28 and 29 to the contact fingers 38 and 84, the current transformer 21b being already connected to these contact fingers by means of the previously traced circuit. The connections of the meters 28 and 29 to these contact fingers may be traced from the contact finger 33 through the conducting segment 84, the conductor 85, the conducting segment 86, the contact finger 49, the conductor 89, the meters 29 and 28, the conductor 68, the contact finger 35, and by way of the lower portion of the conducting segment 18 to the contact finger 35. Thus, it will be seen that the meter 28 is now eifective to give an indication at the master control station I6 of the current flowing in the motor circuit on the vehicle unit B.

The circuit connections for obtaining an indication at the master control station I6 of the current flowing in the motor circuit on the vehicle unit B will be maintained only so long as the control switch 43 is maintained in its depressed position. As soon as the control switch 48 is released, the energizing winding 32 of the transfer switch 30 will be de-energized and accordingly, the transfer switch will return to its No. 2 position to reconnect the meters 28 and 29 to the current transformer 21.

It is believed that it will now be apparent without further detailed description that the same operation may be obtained from any one of the other master control stations regardless of the direction of operation of the vehicle or of the manner in which the vehicle units .A and B are connected together. For example, the units might be connected together with the master control station I 11) on the vehicle unit B adjacent the master control station I6 on the vehicle unit A. Since the control circuits are symmetrical throughout, however, it will be apparent that the operation of the control system will be the same, regardless of the manner in which the vehicles are connected together.

Although I have shown my invention as applied to an alternating current system, in which current transformers are used to derive a suitable current from the motor circuits for energizing the meters, it will be apparent that my invention is equally applicable to direct current installations, in which case the meters may-be energized from suitable current shunts.

In alternating current systems it is imperative that the circuit of the current transformers shall not be open at any time, and accordingly the transfer switches 39 and 3817 are arranged to maintain the current transformers short-circuited while the connections are being changed. As previously described, when the meters 28 and 29 are connected to the current transformer 21, the current transformer 21b is short-circuited through the conducting segment I8 on the transfer switch 38 and it will be seen that when the transfer switch 30 is operated to its No. 3 position, the contact fingers 34 and 35 are maintained short-circuited by the segment 76 until gers 85b and 33b to the 'short-circuited trainwires.

The control system shown in Fig. 1 is applicable only to multiple unit vehicles that may be operated singly or in groups of two in multiple and in Fig. 2 I have shown a modified form of control circuit embodying my invention which is applicable to multiple unit vehicles that may be operated in groups of 1, 2, or 3 in multiple, as the occasion demands.

Referring to Fig. 2, the multiple unit vehicle there shown comprises three separate vehicle units C, D, and E, respectively, which are identical throughout in the construction and arrangement of the control apparatus. As was done in connection with Fig. 1, the unit C will first be described in detail and in the subsequent description of the operation, similar reference numerals followed by the letter at will be used to refer to similar parts of the vehicle unit D, and similar reference numerals followed by the letter e will be used to refer to similar parts of the vehicle unit E.

As shown, the vehicle unit C is provided with a pair of master control stations 81 and 88, respectively, having acceleration and reversing controllers 89 and 90, respectively. The acceleration and reversing controllers 89 and 99 are arranged as described in connection with Fig. 1, the acceleration controllers 89 being arranged to control the operation of suitable acceleration control means indicated diagrammatically by a control box 92, and the reversing controllers 90 being arranged to control a reversing switch 93 provided for controlling the connections of the armature 94 and field winding 95 of a suitable traction motor. As shown, the reversing switch .93 is provided with a pair of operating windings 96 and 97 arranged to be selectively energized through a pair of train wires 88 and 99.

The vehicle unit C is also provided with a transfer switch I99 which is provided with a pair of operating windings ml and I92 and which is identical in its construction with the transfer switch 38, described in connection with Fig. 1, except for the inclusion of an auxiliary pair of contacts I88 and an auxiliary conducting segment I94. As described in connection with the transfer switch. 39 in Fig. 1, the transfer switch I90 is normally biased to its No. 2 position, shown, in which position it is effective to connect a pair of meters I85 and E88 to a current transformer I91 associated with the motor circuit. Upon operation of the transfer switch I98 to its No. l position, the current transformer I9? is connected to a pair of train wires I98 and I89, and upon operatlon of the transfer switch to its No. 3 position,

the meters H95 and I98 are connected to the train wires I88 and I 99. It will, of course, be understood that the meter I95 is located adjacent the master control station 8] and the meter I 05 is located adjacent the master control station 88.

In addition to the above described apparatus, which is similar to the arrangement described in connection with Fig. 1, the vehicle unit C is provided with a pair of three-positioned control switches H0 and III, respectively, which are shown somewhat diagrammatically as drum type controllers, the control switch I I0 being provided with a plurality of contact fingers II2 to I2I, inelusive, and a plurality of conducting segments I22 to I28, inclusive, and the control switch III being provided with similar contact fingers and conducting segments I29 to I45, inclusive.

Adjacent the control switches H0 and III, I provide a pair of auxiliary relays I46 and I41, respectively, which co-operate with the control switches to vary the connections of a pair of train wires I48 and I49. These train wires I48 and I49 are provided with an interlock I50 which connects the train wires together on the leading end of the unit and with jumpers I 5I and I52 which connect the train wires I48 and I49, respectively, to similar train wires M811 and I49d of the vehicle unit D, similar jumpers I53 and I54 being provided to connect the train wires M811 and I49d to the train wires I48e and I49e on the vehicle unit E. Likewise, the train wires I48e and-I49e are connected together on the trailing end of the vehicle unit E by an interlock I55, similar to the above mentioned interlock I50.

It will now be assumedthat it is desired to operate the vehicle in a left-hand direction, as viewed in the drawings, from the master control station 81 and that the reversing drum 90 has been moved to a position corresponding to operation in a forward direction. Upon operation of the reversing drum 90 to this position, energizing circuits will be established through the contacts I56 and I51 on the reversing drum for operating the reversing switches 93, 93d, and 93a, respectively, to the forward position shown in the drawings. Since these energizing circuits are similar to the circuits traced in connection with Fig. 1, it is not believed that it is necessary to.

indication of the current flowing in the motor circuits on the vehicle units D or E simply by moving the control switch I I0, which is associated with the master control station 81, from the No. 1 position to the No. 2 position, or to the No. 3 position, respectively.

It will now be assumed that an indication of the motor current on the vehicle D is desired and that the operator has operated control switch IIO to its No. 2 position. Subsequent to the operation of the 'control switch III) to its No. 2 position, an energizing circuit is established for the transfer switch I00 which may be traced from the positive source of control potential I58 through the contacts I59 of the reversing drum 90, the conductor I60, the contacts H2 and H3 of the control switch IIO, bridged by the conducting segment I22, the conductors I6I and I62, and by way of the operating winding I02 to the ground connection I63. Accordingly, the transfer switch I00 will be operated to its No. 3 position to connect the meter I05 to the train wires I08 and I09 and the subsequent engagement of the auxiliary contacts I03 by the auxiliary segment I04 of the transfer switch will complete an energizing circuit for the auxiliary relay 446d on the vehicle unit D.

This last mentioned energizing circuit extends from the conductor I62 through the conductor I64, the contacts I03, the conductor I65, the contact fingers H8 and III on the control switch III), bridged by the conducting segment I 25, the conductor I66, the contact finger I34 and the conducting segment I42 on the control switch III, the conductor I61, the conducting segment I46 and the contact finger I38, the train line I48, the jumper I5I, the train wire I48d, the conducting segment I28d, the contact finger I2Id, the conductor I68d, the conducting segment I24d, the contact finger IIGd, the conductors I69d and HM, and by way of the operating winding of the relay I46d to the ground connection I63d.

Subsequent to the closure of the auxiliary relay 6d, an energizing circuit is established for the transfer switch I00d, which energizing circuit may be traced from the conductor I'I0d through the conductor IIld, the contacts of the relay I46d, the conductors HM and HM, the contact fingers I32d and I3Id bridged by the conducting segment I40d, the conductor II4d, the contact fingers Sci and I I4d bridged by the conducting segment I23d and by way of the conductor HM and the operating winding IOId to the ground connection I63d. Accordingly, the transfer switch IBM is operated to its No. 1 position to connect the current transformer I0Id to the train wires M811 and I09d, whereupon an indication of the current flowing through the motor circuit on the vehicle unit D may be obtained from the meter I05 at the master control station 81.

An indication of the current flowing in the motor circuit on the vehicle unit E may likewise be obtained at the master control station 81 by simply operating the control switch III! to its No. 3 position. Upon operation of the control switch It to this position, it will be seen that the energizing circuits for the auxiliary relay MM and the transfer switch I00d will be interrupted at the contact fingers Ill and H8 of control switch I I0. Simultaneously, however, an energizing circuit will be completed for the auxiliary relay I41e on the vehicle unit E. It will be observed that the energizing circuit for the transfer switch I00 is maintained through the conducting segment I22 of the control switch H0 and the energizing circuit for the auxiliary relay I41e may be traced from the contacts I03 of the transfer switch I00 through the conductor I65, the contact fingers H8 and H9, bridged by the conducting segment I26, the conductor I16, the contact fingers I36 and I31, bridged by the conducting segment I44, the train wire I49, the jumper I52, the train wire 14911, the contact fin- ,gers Sci and I29d bridged by the conducting segment I21d, the conductor I16d, the contact fingers I36d and I31d, bridged by the conducting segment I44d, the train wire I49d, the jumper I54, the train wire I496, the contact fingers II9e and I20e, bridged by the conducting segment I21e, the conductor I 16c, the contact fingers I36e and I31e, bridged by the conducting segment I44e, the train wire I 496, the interlock I55, the train wire I48e, the contact finger I38e, the conducting segment I45e, the conductor I61e, the contact finger I34e, the conducting segment I42e, the conductors I66e and I11e, and by way of the operating winding of the auxiliary relay I4'Ie to the ground connection I63e.

Subsequent to the closure of the auxiliary relay Ille an energizing circuit is completed for the transfer switch le which may be traced from the conductor l'l'le by way of the conductor "Be, the contacts of the relay Hle, conductors I122 and Se, the contact fingers |32e and IBIe, bridged by the conducting segment Mile, the conductor "4e, the contact fingers 5e and ll4e, bridged -by the conducting segment l23e and by way of the conductorl15e and the operating winding lflle to the ground connection l63e. Upon energization of the operating winding He, the transfer switch liIlle will be operated to its No. 1 position to connect the current transformer lll'le to the train wires |08e and [09c whereupon an indication of the current flowing in the motor circuit of the vehicle unit E may be obtained by means of the meter I05 at the master control station 81.

Similarly, there may be obtained at master control station 88c on the vehicle unit E an indication of the current flowing in the motor circuits of the vehicles D and C by selectively operating the control switch H le to its No. 2 or its No. 3 position. Since the circuits involved are substantially identical with the circuits traced above, it is not believed necessary to trace these latter circuits in detail.

It will thus be seen that I have provided an extremely flexible metering system by means of which an indication may be obtained in the leading vehicle unit of the current flowing in the motor circuits on any one of the trailing vehicles.

I31d and [3801 the circuit to the train wires l48d and 9d leading to the vehicle unit E. For similar reasons, an indication may be obtained at the master control station 81d of the current flowing only in the motor circuits of the vehicles D and E.

While I have shown particular embodiments of my invention, it will be understood, of course, that I do not wish to be limited thereto, since many modifications may be made and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a control system for an electric vehicle having a plurality of motor circuits and a plurality of controllers for said motor circuits, the combination of metering means associated with each of said controllers, and means associated with each controller and including said controller for selectively connecting the associated metering means to any one of said motor circuits.

2. In a control system for an electric vehicle having a plurality of motor circuits and a plurality of controllers for said motor'circuits, the combination of a meter for each controller, and means associated with each controller and including said controller for selectively connecting the associated meter to any one of said motor circuits.

3. In a control system for an electric vehicle having a plurality of separate motor circuits, and a plurality of master control stations for said motor circuits, the combination of metering means associated with each of said control stations, means associated with each of said motor circuits for deriving therefrom a current proportional to the motor current, and means for 5 selectively connecting any one of said metering means in circuit with any one of said current deriving means.

4. In a control system for a multiple unit vehicle having a separate traction motor circuit 10 associated with at least two of the vehicle units and a plurality of master control stations for said motor circuits, the combination of a plurality of meters, each of said control stations having at least one of said meters associated therewith, a current transformer for each motor circuit, and means for selectively connecting any one of said meters in circuit with any one of said current transformers.

5. In a control system for a multiple unit ve- 80 hicle having separate motor circuits for at least two of the vehicle units and a master controller station on each of said units for controlling said motor circuits, the combination of metering means on each of said units adjacent said master 2 control stations, and means including the master controller station on the leading one of said units for selectively connecting the metering means on said leading unit to any one of said motor circuits.

6.'In a control system for a multiple unit vehicle having separate motor circuits for at least two of the vehicle units and master control stations on each unit for controlling said motor circuits, the combination of a meter for each of .35 said master control stations, a current transformer for each of said motor circuits, and means including one of said master control stations on the leading one of said units for selectively connecting the meter associated with said one 40 station to any one of said current transformers.

'7. In a control system for a multiple unit vehicle having separate motor circuits associated with at least two of the vehicle units and master controllers on each of said units for controlling said motor circuits, the combination of a meter for each of said controllers, current deriving means on each of said units respectively associated with said motor circuits, a pair of train wires extending between said units, switch means on 60 each of said units normally connecting the respective meters in circuit with the associated current deriving means, and means including one of said master controllers for operating said switch means to connect to said train wire the meters on one of said units and the current deriving means on another of said units.

8. In a control system for a multiple unit vehicle having separate motor circuits associated with at least two of the vehicle units and master controllers on each of said units for controlling said motor circuits, the combination of a meter for each of said controllers, a current transformer associated with the motor circuit on each of said units, a pair of train wires extending between said units, switch means normally connecting the meters on each of said units in circuit with the associated current transformer, means responsive to operation of any one of said master controllers on any one of said units for operating the switch means on another of said units to connect the current transformer on said other unit to said train wires, and means for operating said switch means on said one unit to connect the meters on said one unit to said train wires. '15

9. In a control system for a multiple unit vehicle having separate motor circuits associated with at least two of the vehicle units and master controllers on each of said'units for said motor circuits, the combination of a meter for each of said controllers, current transformers on each of said units associated with said motor circuits, a pair of train wires extending between said units, transfer switch means on each of said units normally connecting the meters on that unit to the current transformer on that unit, means responsive to the operation of one of said master controllers on one of said units for operating the' transfer switch means on another of said units to connect the current transformer on said other unit to said train wire, and control means adjacent said master controller operable at will to actuate the transfer switch means on said one unit to connect the meter on said one unit to said train wire.

10. In a control system for a multiple unit vehicle having separate motor circuits associated with three of the vehicle units and master controllers on each of said units for controlling said motor circuits, the combination of a meter associated with each of said master controllers, a pair of train wires extending between said three units, transfer switch means for each unit normally connecting the meters on that unit to the associated motor circuit, auxiliary control means associated with each of said master controllers, means responsive to operation of a master controller on one end of one of said units and to operation of the associated auxiliary control means to one position for operating the respective transfer switch means on said one end unit and on the middle one of said units to connect said train wires to the motor circuits on said middle unit and to the ing the transfer switch means on said middle and, the other end one 01 said units to disconnect said,

train wires from said motor circuit on said middle unit and to connect said train wire to the motor circuits on said other end unit.

HAROLD S. OGDEN. 

